Deer have horrible vision - 20/40! They have a 360 degree view horizontally, but they cannot gauge what is directly in front of them, or over their heads. If gardeners don't let deer know that a fence enclosure is ahead, deer may run right into it. This is why gardeners need to add Warning Banners to fences to alert whitetails that a deer fence is near. Banners are most effective when placed on the fence line every 10 feet at a height of 3-4' above ground. Avoid placing warning banners at the top of the fence - this will let deer know how high they need to jump to reach into your garden. Each deer warning banner strip is 1" wide x 24" long and white in color. Pack contains 20 banners, ideal for pairing with 100' rolls of fencing.